Abstract: The coupling device comprises a displacement arrangement for displacing the two waveguide end surfaces relative to one another parallel to the end surfaces and the arrangement has an expansion element that moves the end surfaces relative to one another on the basis of a spatial expansion and/or contraction of the element. With this coupling device tunable optical multi-channel filters with temperature compensation, optical attenuators and waveguide switches can advantageously be realized in a simple manner.

Abstract: The breaking strength of glass fibers, such as generally utilized in optical communication techniques, is materially improved by subjecting a glass fiber to a heat treatment whereby the glass fiber is relatively slowly pulled through a controlled heat zone having a temperature gradient extending from a temperature at or at least relatively close to the softening temperature of the glass fiber to about room temperature.

Abstract: An interferometer with a single mode optical waveguide wound in a coil, which waveguide has an end surface at each end for the acceptance of light into the waveguide and for the emitting of light that is in the waveguide, a beam dividing element for superimposing a portion of light from each of the end surfaces of the waveguide into two separate superimposed beams of light characterized by a polarizer arranged in the path of each of the superimposed beams of light for filtering the light as it is received by a beam receiver, which may be a screen or a light sensitive element such as a photo diode. The beam splitting element may be a beam splitting element having a reflective surface such as a partially reflective mirror or a beam splitting cube or may be optical directional couplers.

Abstract: A process for separating gaseous isotope mixtures having the general molecular composition X.sub.n1.sup.(1) X.sub.n2.sup.(2). . . X.sub.ni.sup.(i), where a constituent X.sup.(k) can be replaced by an isotope X.sup.-(k) by irradiation with laser light.